1. Field of the Invention
The present invention relates to a shelf-type telecommunications device.
2. Description of the Related Art
At present, a shelf-type SONET MUX is widely used as one type of telecommunications device on trunk lines in telephone networks in North America. As demand for telecommunications services has increased in recent years telecommunications devices for integrating a variety of different functions added to the SONET MUX, including data interfaces, ATM switches, etc., have come to be developed.
At the same time, however, the: integration of different functions tends to lead to an increase in the overall size of the telecommunications device. As the amount of space in which to place telecommunications devices tends to be limited, smallness of size is an important factor in such devices.
FIG. 1 is a schematic structural diagram of a conventional telecommunications device 10. The telecommunications device 10 has a shelf structures. To the back of the shelf unit 11 are fixedly mounted a main back wired board 12 and a sub back wired board 13. Additionally, a back cover 14 is attached. Within the shelf unit 11 a plug-in unit 15 is inserted and installed. An external cable 21 is connected to the back of the telecommunications device 10.
The separation of the back wired board into a main back wired board 12 and a sub back wired board 13 exists because the electrical connection between the plug-in unit 15 and the external cable 21 is separated into the electrical connection of the plug-in unit 15 and the electrical connection of the external cable 21. That is, the function of electrically connecting the plug-in unit is assumed by the main back wired board 12 and the function of electrically connecting the external cable 21 is assumed by the sub back wired board 13.
As shown in FIG. 2, the plug-in unit 15 is connected to the plug-in unit connector 16 on the front of the main back wired board 12. The external cable 21 is connected to connector 17 on the sub back wired board 13 via an opening 14a in the back cover 14.
It should be noted that an electrical connection between the main back wired board 12 and the sub back wired board 13 is effected by a coaxial cable 18. However, effecting the electrical connection between the main back wired board 12 and the sub back wired board 13 by using a coaxial cable requires space for connecting the ends of each and every coaxial cable 18.
FIG. 3 shows rear and side rear views of a conventional telecommunications device 10 for integrating a variety of different functions. In keeping with the conventional art, the electrical connection between the main back wired board 12A and the sub back wired board 13A is effected by a coaxial cable 18A. By the integration of different functions the number of coaxial cables approaches 1,000, with corresponding space required for connecting the ends of each of the coaxial cables. As a result, the height Hi of the device 10 increases substantially to approximately 16U, 1 xe2x80x9cUxe2x80x9d being a standardized unit for measuring shelf height and equal to approximately 1.75 inches.
Additionally, as the number of these coaxial cables increases the size of the space 20 required for bending and accommodating the coaxial cables 18A also increases and accordingly, the spacing al between the sub back wired board 13A and the main back wired board 12A must be enlarged to approximately 30 mm. As a result, the depth of the device 10A also increases to a size A1.
Accordingly, it is a general object of the present invention to provide a shelf-type telecommunications device in which the problems described above are solved.
The above-described object of the present invention is achieved by providing a telecommunications device, comprising:
a shelf unit;
a plurality of plug-in units inserted into the shelf unit and disposed side by side;
a main back wired board fixedly mounted to a back of the shelf unit;
a sub back wired board positioned further to the rear of the main back wired board;
a plurality of connectors for plug-in units mounted on an inner surface of the main back wired board so as to be connected to the plug-in units inserted into the shelf unit;
a plurality of connectors for external cables mounted on an outer side of the sub back wired board so as to be connected to external cables;
a plurality of relay connectors mounted on a surface of the main back wired board, the surface opposing the sub back wired board, and electrically connected to the plurality of connectors for plug-in units; and
a plurality of relay connectors mounted on surface of the sub back wired board, the surface opposing the main back wired board, the plurality of relay connectors being electrically connected to the plurality of connectors for external cables,
wherein the plurality of relay connectors on the main back wired board and the corresponding plurality of relay connectors on the sub back wired board are fitted together, and the main back wired board and the sub back wired board are electrically connected to each other.
By providing a telecommunications device in which relay connectors between an opposed main back wired board and sub back wired board are connected, and thus electrically connecting the main back wired board and the sub back wired board, the need for space within which to connect the terminals of the conventional coaxial cable between the main back wired board and the sub back wired board is eliminated. By eliminating the need for such additional space there is little need for the main back wired board and the sub back wired board to increase in size even with an increase in device functions.
Further, the above-described object of the present invention is achieved by providing a telecommunications device comprising:
a shelf unit;
a plurality of plug-in units inserted into the shelf unit and disposed side by side;
a main back wired board fixedly mounted on a back of the shelf unit;
a sub back wired board positioned further to the rear of the main back wired board;
a plurality of plug-in unit connectors mounted on an inner surface of the main back wired board so as to be connected to the plug-in units inserted into the shelf unit;
a plurality of external cable connectors mounted on an outer surface of the sub back wired board so as to be connected to external cables; and
a plurality of pin terminals provided on the plurality of plug-in unit connectors, the pin terminals each having two press-fit portions,
wherein the pin terminals are pressed into and projected through the main back wired board toward the sub back wired board, and tip portions of the pin terminals are pressed into the sub back wire board, and the main back wired board and the sub back wired board are electrically connected to each other.
By providing a telecommunications device in which the electrical connection between the main back wired board and the sub back wired board is effected by plug-in unit connector pin terminals, it is possible to reduce the space between the opposed main back wired board and sub back wired board by approximately one third as opposed to an electrical connection effected by connecting relay connectors between the main back wired board and the sub back wired board.
Additionally, the above-described object of the present invention is also achieved by providing a telecommunications device comprising:
a shelf unit;
a plurality of plug-in units inserted into the shelf unit and disposed side by side;
a main back wired board fixedly mounted to a back of the shelf unit;
a sub back wired board positioned further to the rear of the main back wired board;
a plurality of connectors for plug-in units mounted on an inner surface of the main back wired board so as to be connected to the plug-in units inserted into the shelf unit;
a plurality of connectors for external cables mounted on an outer side of the sub back wired board so as to be connected to external cables;
a plurality of pin terminals provided on the plurality of plug-in unit connectors, tip portions of the pin terminals being inserted into and projected through the main back wired board; and
a plurality of relay connectors mounted on a surface of the sub back wired board, the surface opposing the main back wired board, the plurality of relay connectors being electrically connected to the plurality of connectors for external cables,
wherein tip portions of the plurality of plug-in unit connector pin terminals are connected to the plurality of relay connectors on the sub back wired board, and the main back wired board and the sub back wired board are electrically connected to each other.
By providing a telecommunications device in which the electrical connection between the main back wired board and the sub back wired board is effected by the plug-in unit connector pin terminals and the sub back wired board relay connectors, the need for relay connectors on the main back wired board is eliminated.
Other objects, features and advantages of the present invention will become more apparent from the following detailed description when read in conjunction with the accompanying drawings.